Scopes, particularly those used for hunting, are well known in the prior art. Scopes are generally used to assist hunters in aiming at desired targets. However, because gravity and wind play a role in the trajectory of a bullet by causing the bullet to drop and/or drift to one side of the intended target, hunters have to make adjustments to the scope to account for these effects. Moreover, as the effect of gravity and wind drift on a bullet's trajectory will vary depending upon the distance to the target, multiple adjustments may be necessary at a shooting range or in the field to account for these variances.
To address the above and other related scope adjustment and performance issues, the prior art has developed to include various adjustment knob assemblies. Most commonly, the scope adjustments are implemented in one of two ways. One such way is accomplished by utilizing an adjustment knob assembly that is manually rotated to make the desired adjustments using a screwdriver or similar device. The adjustment knob is covered by a weather resistant dust cap that is usually screwed over the adjustment knob assembly. Problems with these types of assemblies include the time and inconvenience of having to remove the dust cap and the necessity of utilizing a small screwdriver or similar device to effectuate adjustments. During the time it takes to implement these steps, a hunting target may have moved or, in the case of timed shooting competitions, valuable shooting time has elapsed. The second most common way utilizes an adjustment knob assembly that may rotate freely thereby allowing the user to make adjustments quickly. This type of adjustment assembly is generally reserved for scopes used on competition firearms where the firearm is not used in the hunting field but is maintained in a hard case and removed to a shooting bench or platform for competition fire. However, the drawback to this adjustment assembly is that the assembly may be easily knocked out of position and is not designed for field use where a sturdy and weather resistant adjustment assembly is a necessity.
The use of a push pull knob assembly is disclosed in prior art U.S. Pat. No. 6,721,095, entitled “Combined Illuminated Reticle and Focus Knob,” disclosing the use of a push pull turn knob to activate an LED located in the sidewall of a reticle by engaging and disengaging a battery in the turn knob. The turn knob is further used to focus the scope by rotation of the turn knob. While this invention allows hunters to make quick adjustments using a single knob, it does not contemplate a locking device that would keep the knob in either the pushed or pulled position, or from rotating and in fact, does not address the problem solved by the instant invention. The cited art knob may be knocked out of position easily; thus causing the illuminated reticle to turn off or the scope to become unfocused at an inopportune time, such as when attempting to shoot a target.
Clearly there is a need for an adjustable locking knob assembly that allows for quick and easy adjustment of a scope and further prevents the adjustment knob assembly from moving once the desired position is set.